1. Field of the Invention
The present invention is related to agricultural equipment clamps, and more particularly, is directed towards a tool bar clamp which is utilized in agricultural machinery for attaching the shank of a ground-working tool to the tractor mounted tool bar.
2. Description of the Prior Art
The general class of agricultural equipment clamps to which the present invention belongs is well known. In conventional usage, such clamps are utilized as means for interconnecting ground-working tools with a tractor or other motive machine. Generally speaking, such machines utilize a square sectioned hollow tool bar which extends transversely to the direction of travel of the machine. A plurality of agricultural equipment clamps are connected to the square tool bar along the length thereof. The clamps generally include means for securing a generally rectangular shank of an earth-working tool thereto in a transverse, generally vertical, relationship to the tool bar.
The shanks of the tools secured in the clamps extend downwardly to their respective earth-working implements, the shanks generally positioned rearwardly of the tool bar. In a typical agricultural machine such as a cultivator, there may be as many as eighty such clamps secured to a single tool bar for supporting eighty earth-working implements.
In view of the foregoing, it may be appreciated that the construction, strength, and weight of each individual clamp can be of paramount importance in calculating the overall efficiency of the agricultural machinery. The design of such clamps must be such as to easily withstand the torques generated about the tool bar while maintaining the earth-working implement in the desired position. Further, the design should preferably enable quick and easy adjustments of the height of the tool shank, as well as permit easy changing of shanks should the associated implement require repair. Such clamps must be able to withstand large forces, as well as provide positive clamping of both the tool bar and tool shank during use. The clamp should preferably be impervious to outdoor weather conditions, and be designed with sufficient structural rigidity so as to withstand externally provided impact forces or shocks which may be imparted thereto.
Weight considerations are of particular significance. Prior art agricultural equipment clamps of the type described have generally been formed of cast steel which has resulted in a total weight of approximately six to eight pounds per clamp. When one takes into account the large number of clamps which may be utilized on a single piece of machinery, weight considerations are significant in terms of the total wear and tear on the machinery, the total power and fuel required to operate same, and the general difficulty encountered in manually handling heavy equipment. It can therefore be appreciated that any savings in weight in the design of such clamps would be highly desirable, provided that structural integrity and reliability were maintained.
U.S. Pat. No. 3,550,969 to Robinson illustrates a typical prior art agricultural equipment clamp of the general class described hereinabove. Robinson's clamp is characterized by a pair of closely spaced tool shank seats 28 and 29 formed internally of the clamp body, the outer portions of which serve as the body's V-shaped tool bar seat. The tool bar is secured between the cap and the body by a pair of bolts which extend through cooperating bolt ears which extend laterally from both the body and clamp. A shank set screw extends through the top of the body to urge the tool shank against its respective seats 28 and 29.
While generally being an improvement over clamps previously known, the Robinson clamp nevertheless suffers from several deficiencies. One of the deficiencies concerns the casting of the clamp out of steel, which results in a rather heavy product that cumulatively increases wear and tear, requires greater power and fuel, increases ground compaction, and generally reduces efficiency. Further, the Robinson design provides a tool shank seat comprised of a pair of closely spaced seating points which tend to withstand less torque than would be the case if such points were more widely separated. Other deficiencies include the requirement for at least two tools in order to tighten the cap to the body of the clamp, as well as the difficulty encountered in properly aligning the set screw nut over the set screw aperture in the back spacing block. Finally, the bolt ears of the Robinson design can be subjected to severe shocks and forces which tend to fracture and break the ears from the clamp body.